1. Field of the Invention
The present invention relates to a method and a device for clearance adjustment for a lead-in roller clearance adjustment mechanism which is suitably applied to a web processing machine for processing web members such as paper, films, woven fabrics or non-woven fabrics.
2. Description of the Related Art
In the following description of the related art, paper is used as an example of the web members, and a web rotary printing press is used as an example of the web process machine, for the purpose of facilitating understanding of explanations. In this context, a web thickness will be described as a paper thickness, and an automated web threading device configured to thread the web member automatically into a web transport path in the web processing machine prior to starting web processing will be described as an automated paper threading device in the following description of the related art.
In the web rotary printing press, paper threading is executed when a task is changed due to printing specifications and the like or when the paper runs out in the course of machine operation. Here, it is a well-known technique to provide the automated paper threading device for the purpose of speeding up and saving labor of this operation (see Japanese Publication of Unexamined Utility Model Application No. Hei-1(1989)-103647).
Moreover, in terms of a lead-in roller clearance adjustment mechanism provided downstream of a former of the web rotary printing press, a clearance between a pair of lead-in rollers is widely opened so as to pass that lead (adopter) or the like smoothly when the automated paper threading device executes paper threading into that lead-in roller unit. Meanwhile, after completion of the paper threading, a clearance is adjusted to correspond to a paper thickness of the web passed therethrough so as to effectuate favorable former fold (see Japanese Publication of Unexamined Utility Model Application No. Hei-4(1992)-9853).
However, in the conventional lead-in roller clearance adjustment mechanism, all the above-mentioned clearance adjustment operations have been executed manually. As a consequence, there are problems of a burden on an operator and of time consumption. Moreover, since adjustment accuracy is poor and there is no reproducibility because of the manual adjustment, the operator is often required to visually check a condition of the web at the lead-in roller unit and to perform fine adjustment at the time of starting printing; or the operator is often required to visually check the condition of the web at the lead-in roller unit and to perform fine adjustment during the operation. Hence there are also problems of a burden on the operator and of occurrence of wasted printing materials.